In order to properly transmit signals to subscribers, a communication satellite needs to be accurately calibrated. Although a satellite may be initially well-calibrated, over time, and particularly in the harsh conditions of space, the calibration can drift, requiring recalibration. Beamforming satellites transmit a signal from several antennae that form a beam at chosen locations though constructive and destructive interference between the different signals. Beamforming satellites must be calibrated to a set of requirements that are tighter than those for a non-beamforming satellite as the gain, phase and delay must be accurately calibrated so that the different transmitted signals constructively interfere properly at the desired location.